Piston, plunger, and the like.



A. R. TRIST.

PISTON, PLUNGER, AND THE LlKE.

APPLICATION FILED MAR. 22. 1916.

V 1,234,972, Patented July 31, 1917.

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, rrs'ron, PLUNGER, AND THE LIKE.

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Specification of Letters Patent.

Patented July 31, 1917.

Application filed March 22, 1916. Serial No.85,753.

To all whom it may concern:

Be it known that l, ARTHUR RONALD 'Tnrs'r, subject of the King of Great Britain and Ireland, residing at Coronation House, a Lloyds avenue, in the city of London, England, have invented new and nseful Improvements in and Relating to Pistons,

Plungers, and the like, of which the following is a specification. 7

This invention relates to improvements in pistons, plungers and the like pf the type in which a fibrous packing is employed to prevent leakage and has for its object the provision 'of'means whereby a piston or plunger .is produced having a very high volumetric and mechanical efficiency ascompared with known pistons or plungers and in which automatic compensation for wear is rendered possible within wide limits while at the same time the cost of manufacture and up keep is reduced to a very low amount. I

The invention consists in the arrangement in the working surface of the piston or plunger, of a rin or rings of fibrous or other elastic pac ing. material normally .and being augmented to a. more or less extent by the workin pressure against which the active end of t e piston is operating.

In order that the invention may be the better understood I will now proceedto describe the same in relation to the accom panyin'g drawing, reference being had to the letters and figures marked thereon. Like letters refer to like parts in the various figures, in which Figure, 1 is an elevation of a ring constructed in accordance with my invention.

Fig. 2 is a section thereof. .Fig. 3 is a section illustrating one method pf construction and showing its laminar orm.

' showing a single acting piston with one of Fig. 4 is an elevation partly in section rectangular form the greatest dimension 6 of the rectangle being parallel to the axis 0 c of the ring a. Parts 03 05 of the top and bottom' inside edges of the section are removed (see Fig. 3) and bevels e are provided in place thereof. The outer or working face f of the ring a is divided by a groove 9 which is disposed substantially in the middle of the face f and in which if so desired lubricating material can be inserted while to obviate any hoop stress in the ring a during use a conduit h (shown dotted in Fig. 2) can be provided from the said groove so as to directly communicate with the interior of-the ring w.

This ringa may be of laminar construction as shown in Fig. 3 and it has been found that the best results. are obtained when layers 21 offibrous or metallic fabric are embedded in a matrix of cementit'ious or vulcanizable material and vulcanized in position when a vulcaniz'able material is employed. The layers '11 are preferably so disposed that the edges 71 of the said fabric provide the working surface f of the ring.

'I have, found that the following relative dimensions give satisfactory results with ordinary pressures such as 100 lbs. to 600 lbs. persq. in.; but it is'obvious that considerable modifications may be effected withoutdeparting from the invention. Taking thle width b as a unit, the'width of the end surface. 0? equals i b, the width of the interior surface a" equals the width of the groove, g'which equals %,-rd 6, the depth of the groove g equals .gth b and the total thickness of the section 'equals b.

A single acting iston adapted to deal with pressure as 1n icated by the arrow 4 is illustrated in Fig. 4 and is provided with a fixed abutment Z having an annular surface Z adapted to conform with and support one of the. end surfaces J and the bevel surface 6 of the ring a and a member an axially movable relative to the fixed abutment Z, the said member m having an annular surface m adapted to engage with the bevel surface 6, the other end surface 03' and the remainder a of the interior surface of the ring a. The movable member m is maintained in place by aneans of the spring n which abuts against the nut 72. carried'by the projection l of the fixed abutment Z the said spring 0?. exerting suflicient pressure to hold the ring a in position and expand it so that the said ring a closely contacts with the cylinder at all parts of its working face.

In this construction it will be seen that the working pressure can pass through the passage m to the interior surface of the member m and thus effect a partial counter balance thereby more or less relieving the ring a of the resultant pressure upon the exterior surface of the member m, due to the working pressure.

A double acting piston is illustrated 1n. Fig. 5 andhas two rings a a with their respective abutments Z Z and movable members m, m, associated in opposition to each other, the said movable members m m being maintained in operative position by springs n n, and to admit pressure from the alternate working ends of the piston to the space between the movable members on m so as to permit of freedom of operation of said members m m an automatic valve ;0 is provided the said valve 0 being adapted to simultaneously prevent passage of fluid from one side of the piston to the other through the intervening space. In exceptional circumstances the rings a a may be supplementedwith duplicate rings acting in tandem therewith a sufficient number of duplicate rings being provided at each end of the pistonif it is double acting as may be necessary to safeguard against leakage.

Owing to the very high volumetric efliciency possible when a piston constructed according to this invention is used in association with a cylinder and also the very high mechanical efficiency obtainable due to its frictionless properties it is particularly adapted for use in regulating apparatus due to its lack of leakage and its capability of dealing with very high and very low or even negative pressures without adjustment.

1 claim 2- 1. A piston or the like provided with an annular groove in its periphery having beveled surfaces on its side walls, two axially spaced packing rings positioned within the piston groove at the opposite sides thereof, each of the said rings having oppositely beveled interior faces, one of which contacts with the adjacent beveled face of the piston groove, and two relatively spaced abutment members mounted within the said groove between the packing rings and having beveled side faces for contact with the other beveled faces of the adjacent rings, the said abutment members being constructed so as to present adjacent inner surfaces of comparatively large area and the piston being provided with a fluid conduit extending between the inner part of said groove and the exterior of the piston to admit workingpresintents 2 sure to the, space between the abutment members. 1

' 2. A piston or the like provided with an annular groove in its periphery having beveled surfaces on its side walls, two axially spaced packing rings positioned within the piston groove at the opposite sidesthereof, each of the said rings having oppositely beveled interior faces, one of which contactswith the adjacent beveled face of the piston.

groove, two relatively spaced abutment members mounted within the said groove between .the packing rings and having beveled side faces for contact with the other bevel faces of the adjacent rings, the said abutment members being constructed so as to present adjacent inner surfaces of comparatively large area and the piston being 3. A piston or the like provided with an annular groove in its periphery having beveled surfaces on its side walls, two axially spaced packing rings positioned within the piston groove at the opposite sides thereof, each of the said rings having oppositely beveled interior faces, one of which contacts with the adjacent beveled face of the piston groove, two relatively spaced abutment members mounted within the said groove between the packing rings and having beveled side faces for contact with the other bevel faces of the adjacent rings, the said abutment members being constructed so as to present adjacent inner surfaces of comparatively large area and the piston being provided with a fluid conduit extending between the inner part of said groove and the ARTHUR RONALD TRIST.

Witnesses WALTER CARVER, DORIS Hrror'roocn. 

